I've never been a direct caregiver. But I have given care to the caregiver. My grandma went downhill with pancreatic cancer in a hurry when I was in high school. She came to live with us for the last year or so. It was rough on my folks, it was my mom's mom, but my dad worked at home a lot so he had a lot of daily care responsibility as well.
I was 16 or 17, so I had a license and wasn't a kid that couldn't help out. So they would go away for a weekend now and again and I'd be the one doing everything for her.
My old man got sick with gastrointestinal cancer a few years back. I lived several hours away at the time, but I would try to visit once a month or so. I'd cook and clean and run errands for my exhausted mom, and keep him occupied by talking or playing games with him. His mind was shot from a lack of nutrition and hardcore pain meds and any activity with him got to be tedious and repetitive. In lieu of a fancy funeral, he wanted to set up a scholarship fund for someone going into nursing since they cheerfully scrubbed his ass and balls toward the end. My mom was overwhelmed by it, but I just said fuck it, got in touch with some local charities, and now we've awarded one two years straight.